Spray nozzle

ABSTRACT

Improved airless spray nozzles and methods and means for making them. A spray nozzle tip having a central longitudinal passage terminating in an outlet orifice is provided with a single lateral inlet to the passage. The opposite open end of the passage is closed to form a turbulence chamber by means which may be removable or detachable and may be yielding or resilient. The lateral inlet is related in size to the outlet orifice and is in the form of a slot having transverse faces which lie in planes that intersect in a line which lies in a plane normal to the longitudinal axis of the passage. The nozzle tip may be mounted in a carrier. The nozzle tip is readily cleanable by a cleaning probe inserted through the lateral inlet. The nozzle tip is made from a preformed blank having an internal passage by a grinding wheel of the proper shape and size. The effective areas of the inlet and outlet orifices are determined during their cutting by passing air through the passages and measuring the rate of flow from the lateral inlet and from the outlet orifice.

United States Patent Rood [ 51 Apr. 25, 11972 [54] SPRAY NOZZLE [72]Inventor: Alvin A. Rood, Westlake, Ohio [73] Assignee: NordsonCorporation, Amherst, Ohio [22] Filed: Sept. 11, 1969 [21] Appl. No.:856,983

52 U.S.Cl ..239/589,239/597 s11 lnt.CI. ..A0lq25/04 [58] FieldofSearch.....239/s9o.3,s99, 601,589,597, 239/598, 412, 602, 284, 483,468,592,593, 594,

FOREIGN PATENTS OR APPLICATIONS 122,344 7/1948 Sweden ..239/589 256,7355/1964 Australia ..239/547 Primary Examiner-M. Henson Wood, Jr.Assistant Examiner-Edwin D. Grant Attorney-Bosworth, Sessions,l-Ierstrom and Cain [5 7] ABSTRACT Improved airless spray nozzles andmethods and means for making them. A spray nozzle tip having a centrallongitudinal passage terminating in an outlet orifice is provided with asin gle lateral inlet to the passage. The opposite open end of thepassage is closed to form a turbulence chamber by means which may beremovable or detachable and may be yielding or resilient. The lateralinlet is related in size to the outlet orifice and is in the form of aslot having transverse faces which lie in planes that intersect in aline which lies in a plane normal to the longitudinal axis of thepassage. The nozzle tip may be mounted in a carrier. The nozzle tip isreadily cleanable by a cleaning probe inserted through the lateralinlet. The nozzle tip is made from a preformed blank having an internalpassage by a grinding wheel of the proper shape and size. The effectiveareas of the inlet and outlet orifices are determined during theircutting by passing air through the passages and measuring the rate offlow from the lateral inlet and from the outlet orifice.

31 Claims, 11 Drawing Figures PATENTmmzs I972 3, 658 257 sum 1 0F 3 HYfi MZIM a ATTORNEYS SPRAY NOZZLE SUMMARY OF THE INVENTION An object ofmy invention is to provide an airless spray nozzle which in a very smallsize and capacity will produce a more perfect fan pattern, fineatomization and a very quick breakup of the liquid film very close tothe outlet orifice at the root of the fan. Such a nozzle makes possiblethe airless coating of the interior of small tubes and vessels. Anotherobject is to provide a side inlet port for such a nozzle, as well as forlarger ones, that is easily cleaned, and is capable of producing morereadily a benign turbulence in the fluid stream at, in and/or beyond thedischarge orifice.

My invention is also concerned with reducing or preventing clogging ofairless spray nozzles, and, colaterally, with cleaning nozzles that havebecome wholly or partly obstructed. This matter becomes more criticalespecially in small nozzles that are used to spray paint in which solidor congealable constituents are present. My invention provides a singlelarge" inlet port for the nozzle tip of size and shape having a lessertendency to clog than the outlet orifice instead of following priorpractice of using two or more small" inlet ports. My invention alsodisposes the nozzle tip in the nozzle structure in a way that freelyexposes the inlet port as well as the outlet orifice to cleaning probesand other ways and means to clean the tip.

It is also among the objects and accomplishments of my in vention toprovide a new method of making side inlet nozzle tips and also toprovide improved closures for such tips as they are employed in completenozzle assemblies attached to spray guns.

An embodiment of my invention comprises a nozzle tip having an annularwall and a longitudinal passage within the wall open at one end andleading to a discharge orifice at the other end with a lateral inletport spaced between said ends. The lateral inlet port is cut through thewall in substantially the form of a slot having flat transverse faceswhich lie in converging planes that intersect in a line that lies in aplane normal to the longitudinal axis of the passage. The bottoms of theslot lie in opposite parts of the wall. The lateral inlet port directsfluid into the passage transversely of the longitudinal axis of thepassage. That portion of the passage between the lateral inlet port andthe outlet orifice defines an approach passage to the outlet orificewhile the portion between the closed end and the approach passagecomprises a turbulence chamber.

The method of making my spray nozzle tip from blank stock having acentral longitudinal passage open at one end includes the steps ofcutting through the end wall of the blank to the passage to make theoutlet orifice and measuring the effective size of the outlet orificewhile it is being made by causing a fluid under pressure to flow throughthe orifice and measuring the rate of flow. Further steps includecutting through the side wall of the blank to the passage to make theinlet port orifice, measuring the effective size of that orifice, or theparallel sum of the two, in the same way that the effective size of theoutlet orifice is or was measured, and relating the effective sizes ofthe two orifices to each other according to the relative rates of flowof the fluid therethrough.

BACKGROUND OF THE INVENTION 1. Field of the Invention My invention liesin the field of Sprayers and Spraying Nozzles and relates particularlyto the field of spray nozzles of relatively small gallonage delivery ascompared with the nozzles for lawn sprinklers and fire hoses. One field,for example, in which nozzles embodying this invention have especialutility, is that of hydraulic airless spraying of paint in flat fanspray patterns in which the sizes of the nozzles are such that thegallonage flow of water at 500 p.s.i. is between about 2 to gallons perhour. My invention also comprehends spray nozzles for spraying liquidsand fluids other than paint. One aspect of the field of this inventionrelates to spraying with fine atomization in small spray patterns withvery small liquid films or sheets extending beyond the nozzle orifice. Aparticular field is spray coating the interiors of small tubes, pipesand vessels having an inside diameter of about one-half inch, forexample.

2. Description of the Prior Art As presently informed, the mostpertinent prior art comprises the invention or improvements disclosed inthe copending applicationof myself and others, Ser. No. 731,062 filedMay 22, 1968 and, more remotely, the prior patents and practicesreferred to in that application. Mention is also made of the Wahlin U.S.Pat. No. 2,745,701 for the conventional teaching about the V-slotdischarge orifice in the dome of the nozzle tip and about the approachpassage thereto. Pertinent prior art also comprises the prior public useand sale by Nordson Corporation, assignee of my invention, of one ormore of the embodiments of the invention contained in my said priorpending application.

These exemplifications of the prior art have taught the use of spraynozzle tips wherein the fluid to be sprayed was forbidden to enter thenozzle tip in the direction of the longitudinal axis thereof. Moreparticularly, the fluid to be sprayed was required to enter the nozzletip laterally, as by opposing streams meeting in collision near theupstream end of the approach passage, whereby to induce turbulence inthat passage. In the prior Carroll U.S. Pat. No. 2,522,928 and FischerU.S. Pat. No. 1,151,258, both discussed in my co-pending application,see also Danielsson U.S. Pat. No. 1,657,372, the approach passage wassubstantially non-existent or of such short length, as to fail tofunction as an approach passage.

In this prior art, lateral inlets to the approach passage were knownwhich intentionally, or by virtue of manufacturing difficulty, induced,or tended to induce, a swirling motion in the fluid stream moving to thenozzle orifice which was detrimental to the flat fan pattern of thespray sought and obtained by my invention.

The prior art has failed to teach ways and means of gaining fineatomization with a very short, almost minute, turbulent liquid film onthe atmospheric side of the nozzle discharge orifice especially in smallnozzles, has failed to teach the kind and disposition of lateral inletwhich I have provided in my present invention, has failed to provideways and means to prevent clogging, and facilitate cleaning, of nozzletips and nozzles, and has, among other things that will appear herein,failed to teach methods and means for forming the inlet passage inand/or making or mounting nozzle tips embodying my invention.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a longitudinal section of one ofmy small nozzles disposed within a small tube in position to spray andcoat the interior thereof.

FIGS. 2 and 3 are a side elevation, partly in section, and a frontelevation, respectively, of a fixture and cutting wheel for cutting andsizing a side inlet port in the nozzle tip of FIG. 1.

FIG. 4 is a longitudinal section of another form of nozzle embodying myinvention comprising an adapter carrying a two-piece nozzle tip andclosure.

FIGS. 5 and 6 are side and front elevations, respectively, of a fixtureand wheel for holding, cutting and sizing the side inlet in one part ofthe two-piece nozzle tip of FIG. 4.

FIG. 7 is a longitudinal section of a modified form of my inventionmounted on and assembled with the forward end of a spray gun.

FIG. 8 is a longitudinal sectional view of a modified form of the nozzletip of FIG. 7 with the closure plate of FIG. 7.

FIG. 9 is an isometric view of the nozzle tip of FIG. 8 taken from theupstream end and showing the lateral inlet thereof.

FIG. 10 is a longitudinal sectional view corresponding to the view ofFIG. 7 showing however a modified form of nozzle tip and end closuretherefor embodying my invention.

FIG. 11 is a top plan view of the rearward part of the nozzle tip Ttaken along the line 11-11 of FIG. 10.

DESCRIPTION OF PREFERRED EMBODIMENTS The nozzle tips l-S incl., shown indifferent specific forms in FIGS. 1, 4, 7, 8 and 9, and 10,respectively, shall in this description comprise that part ofeach oftheseveral nozzle assemblies N N shown in same Figures, which embraces aconventional, flat-fan, discharge orifice 0, having an approach passageP leading thereto, a novel side inlet port I l and a turbulence chamberT T The two-part nozzle tip in FIG. 4 comprises an orthodox forward part2, and a separate, novel, rearward part 2 which together embrace theapproach passage P and, the turbulence chamber T and the end closuretherefor. The term, turbulence chamber, will be used herein, somewhat asin my co-pending application, to designate that portion of the wholeinternal void or passage in my nozzle tip which is l) longitudinallyopposite the approach part P of the whole internal passage, (2) adjacentan inlet I I,-, and (3) also between an inlet and the closed end of thewhole internal passage. These turbulence chambers T, of FIG. 1; T ofFIG. 4; T of FIG. 7; T of FIGS. 8 and 9; and T of FIG. 10, are theplaces where violent agitation and, probably gross, directional,turbulence of the fluid to be sprayed is generated and supplied toapproach passage P. The whole internal void or passage in each of itsspecifically different forms disclosed herein may be referred to as theinternal passage P-T P-T etc. as the case may be.

I prefer, as shown in each form of my invention, that the whole internalpassage taper in cross-sectional area from greater to smaller betweenthe turbulence chamber and the discharge orifice whereby to acceleratethe movement of the turbulent fluid stream from the former to thelatter. I also prefer that the length of the approach passages P,measured from the center of the dome through which the gash of thedischarge orifice O is cut to the nearest aspect ofthe inlet port I l befrom about four to seven times the mean diameter of said dome. Improvingupon the the invention of my co-pending application, the smaller ratiosmay be used in a small size nozzle tip as shown in FIG. 1, having agallonage flow of water at 500 p.s.i. of as little as 2 or 3 gallons perhour.

The turbulence created in the turbulence chamber incident to thevigorous, angled introduction of the fluid thereinto, the abrupt changeof direction of the fluid stream from substantially normal to, toparallel with, the axis of the internal passage, and the cut and thrustbetween the streams entering and leaving the chamber, tends, as Ibelieve, to be gross and directional, probably following discerniblegross paths and/or patterns, which, if present at and in the sprayorifice 0, would detract from the excellence ofthe fan and spray patternthat is sought to be projected from said orifice. The business of theapproach passage is to convert the gross and/or directional kind ofturbulence made in the turbulence chamber into, and combine it withupstream turbulence in the approach passage, to create and promote auniform pattern of minute random turbulent motions with uniform forwardvelocity across the whole cross-section of the fluid stream adjacent, inand through the spray orifice O.

The work of the approach passage is more burdensome or less burdensomeaccording to the adverse or beneficent influence of the lateral inletport. Prior to my present invention, side inlets to spray nozzles,intentionally or inadvertently, tended to induce helical or spiraldirectional swirling of the fluid stream near, at and/or in the nozzleorifice where the core of the inlet stream departed from a true radiusof the nozzle tip. The inlets or ports 1 I in this preferred form of myinvention are designed, formed andlocated in the tip to introduce fluidinto the turbulence chamber with a beneficent influence tending tohasten and enhance the creation of benign, minute random turbulence inthe approach passage and at, in and beyond the spray orifice.

The inlet ports l FIGS. 4, 7, l0 and 11, show the principle ofmy portdesign in a form which I prefer. The port 1 FIGS. 8 and 9, is formed atthe end of the nozzle tip 4, and is the more easily illustrated in theisometric view of FIG. 9. It may be formed, however, in substantiallythe same way that the port I is cut in the part 2 of the two-piecenozzle tip 2-2 ofthe nozzle N FIG. 4, as shown in FIGS. 5 and 6. Thetwo-piece nozzle tip of FIG. 4 employs only the side inlet port I; inthe rear' ward part 2 and employs only the discharge orifice O in theforward" part 2. My method of gauging the relative effective sizes ofthe inlet and outlet orifices is simplified in this twopiece tip form aswill more fully appear below in discussing the gauging of the inlet andoutlet orifices I, and 0 when the same are embodied in the same tip.Here in FIGS. 5 and 6 the blank Q has its internal void or half-passageP pre-formed therein with no outlet cut through the dome D, norelsewhere, and as held horizontally in a fixture F with its blind, leftas viewed, end firmly secured in a socket S. About half the length ofthe blank, and the open end of the blind passage is exposed without thefixture to the cutting and slotting action of a diamond cutting wheel Wof many, preferably about thirty, times the diameter ofthe blank.

The wheel W conveniently has double conical peripheral edge formationsl0 and 11 tapering at 20 from greater radially inward thickness to anarrow right, circular, cylindrical periphery 12. The wheel W is rotatedconveniently about an axis a-a in the same plane as, and in this caseparallel with, the longitudinal axis LL of the blank Q. The width of theperiphery 12 measures the axial dimension of the flat chordal faces 15,FIGS. 9 and 11, and measures approximately the axial dimension of theinlet port orifices 0', FIG. 9, and 0", FIG. 11. In FIG. 9 the dottedline at the near side ofthe orifice 0 suggests the boundary effected bythe planar closure of the end of the nozzle tip N, by the plate 17 (FIG.8). The lateral dimension of the orifices O and 0" depends upon thedepth of the cut which the wheel W makes in the blank Q, i.e. how nearlythe periphery 12 comes to the diameter of the internal passage.Presently, l have found and believe that the orifices O and 0 may havean approximately square shape about as shown in FIGS. 9 and 11 andfunction to good advantage.

As shown in FIGS. 9 and 11, the flat faces 15 intersect the adjacentinterior side" surfaces of the internal passage in the tip at an acuteangle. As presently advised these faces, so disposed, tend to constrictthe stream of fluid entering the passage through the port to a smallertransverse dimension, i.e. vena contracta, than the width of the portorifice and the passage. This, I believe, makes room for turbulent fluidto move rapidly and violently from the turbulence chamber past theentering stream into the approach passage. Also, the entering stream isaccelerated by constriction to impinge more violently on the surface ofthe passage opposite the port to induce greater and/or more benignturbulence. I prefer, as shown in all the within forms of my nozzle tipexcept in FIGS. 8 and 9, that the inlet port be located about midwaybetween the ends of the internal passage and afford a turbulence chamberof volume comparable to the volume of the approach passage. 1 alsoprefer as shown in all the within forms of my invention that the inletport be cut transversely across the side of the nozzle tip.

These inlet port orifices, respectively, comprise the sole entrance tothe nozzle tip, and have, as I prefer, no smaller minimum dimension normore restricted configuration than the corresponding discharge orifices0 whereby to avoid clogging, and thereby starving the dischargeorifices. The whole, more particularly the effective, areas of the inletorifices approximately correspond, respectively, to those of thedischarge orifices, plus or minus about 25 percent depending on factorsand conditions known to users of the Nordson LV" nozzles disclosed in mysaid pending application, including gross flow, nature and viscosity ofthe liquid being sprayed, the spraying temperature and pressure, filmthickness desired and the kind of fan and fan pattern desired and thekind of surface being sprayed or coated.

As viewed in FIGS. 5 and 6, the wheel W is mounted above the fixture Fso that it cuts a slot 13 into the upper side of the blank Q as the axisa-a is lowered toward the blank. So long as the axis a-a is maintainedparallel to the axis LI. and is lowered truly vertically downwardly, asI prefer, the slot 13 will be cut symmetrically into the wall 14 of theblank Q, see FIG. 9, so that flats 15, FIGS. 5, 6 and 9, will be equal,and lie, in this instance, symmetrically related to the approachpassage, in substantially the same chordal plane relative to the axisL-L of the blank 0. For the same reason the transverse faces 16 of theinlet port 1 FIG. 11, are equal and are symmetrical to the axis L-L, andintersect in a line which lies in a plane normal to the axis L-L. In theinlet ports I, and I FIGS. 1, 8 and 9, the transverse faces of the slotsare not equal but they all lie in planes which meet and intersect in aline which lies in a plane which is normal to the axis of the nozzle.

It presently appears that the angular relation around the axis L-Lbetween the inlet ports I,-I and the discharge orifice O has littleinfluence upon the excellence of the spray pattern which is projectedthrough the orifices, particularly, as long as relationship between theinlet ports, approach passage and turbulence chamber follows mypreferences expressed herein. Present experience suggests my preference,however, that one or the other of two apparently optimal angularrelations between the inlet port and the discharge orifice be employed.So, in FIG. 1, the overall length of the slot of the inlet port lies atright angles to the overall length of the gash of the discharge orifice.This puts the spray fan longitudinally of the tube 34. In FIGS. 4, 7, 8and 10 the overall lengths of the ports and orifices are parallel andperform quite well.

Because the diameter of the preferred form of my cutting wheel is muchgreater than the diameter of the nozzle tip, the arc of the wheel in theslot 13 is nearly flat in respect to the flats 15. Alternatively theaxis a-a of the cutting wheel may be given a horizontal right and leftmotion as viewed in FIGS. 3 and 6 for each increment of downward motionwhereby to make the flats l5 truly planar and chordal as well assymmetrical to the internal passage in the tip. Should the wheel begiven such right and left motion relative to the tip as the cuttingproceeds the axis of the wheel and the axis of the tip should beconstrained to move together in a moving vertical, as viewed in FIGS. 3and 6, plane. This will give a truly transverse cut and will tend togive a desirable true, fine edge to all the sides of the inlet orifice.As shown in FIG. 2, it is more generally accurate to teach that the axesof the wheel and the tip should lie in the same plane, than to emphasizethat they be parallel; the latter being incorrect when the inlet port isto be inclined as shown in FIGS. land 2.

To make the inlet orifice I, in the part 2 of FIG. 4 of a particularsize, a known type of air gauge hose and/or fitting, not shown, isconnected to the exposed open end of the passage P as at 20, FIG. 5,while the blank Q is secured in the fixture F. Then, at intervalsbetween cutting engagements of the wheel with the blank, air is blowninto the passage and out through the partially cut slot for the portwhilst the flow of air at a predetermined pressure is measured by anappropriate flow meter, not shown. Cutting of the slot is continueduntil the desired rate of flow of air is obtained. The inlet port thenhas acquired a particular, determined effective area. Since the outletorifice O is to be, or has been, cut in the other parts of the tip 2-2,its effective size has been, or can be, gauged and measured in the sameway, and related to the effective size of the port exactly as may bedesired.

Referring now to FIGS. 1, 2 and 3, cutting the inlet port I, in the tip1 first requires that the blank 0' be secured in the fixture Fwherewithto be worked by the cutting wheel W in much the same way andfor the same purpose and effect as described above with reference toFIGS. 5 and 6, having regard for the specific form of the intake port I,employed in the tip I. As suggested in FIG. 1, the inlet port I, istipped rearwardly away from the nozzle orifice O to accommodate theangled disposition of the tip in the carrier portion 30 of the adaptor31; the forward face 21 of the port lying substantially normal to theaxis of the tip and passage P, and the rearward face 22 being inclinedrearwardly about 40 from normal to the axis. This inclination of theport accords with the inclination of the tip in the nozzle and serves todivert the flow of liquid, left to right, as viewed, from the adapter 31into the passage P at approximately right angles to the axis of the tipand passage whereby to create great, desirable turbulence in the chamberT, and in the passage P.

The fixture F is employed to facilitate cutting the slot in the blank Qto make the inclined inlet port I,. The fixture comprises a base ofconvenient form and upper structure characterized by a notch 23 toreceive the cutting wheel W with generous clearance and to expose theupper surface of the blank Q to the wheel. The fixture F is alsocharacterized by an inclined hole 24 having a smooth cylindrical lowerportion with a conical counterbore 28 wherein the body of the blank Q,with its conically tapered forward end 25, is firmly secured by a hollowscrew 26 threaded into the tapped upper port 27 of the hole 24.

The blank Q when secured in the fixture has its preformed internal voidor passage open at its upper, leftward end, as viewed in FIG. 2, andshown in section in FIG. 1 at its lower, leftward end. The domedterminus of the passage preferrabiy has been slashed to make thedischarge orifice O, and the orifice is temporarily plugged while theinlet port is being formed. The hollow screw 26 engages the open end ofthe blank tip to secure the same in the fixture, and it also provides anairtight air passage to and with the then blind passage in the blank. Asin the procedure explained with reference to FIGS. 5 and 6, an air lineis connected to the exposed end of the screw 26 as at 20', and theextent of the cutting to form the inlet port is measured by the flow ofair at its predetermined pressure to correspond with or relate to, theflow theretofore measured through the discharge orifice, i.e. to theknown effective size of the discharge orifice.

Alternatively the discharge orifice 0 having been cut and gauged bymeasuring the flow of air therethrough, as taught above, may be leftopen while the inlet port I, is being cut. In this event the desiredeffective size of the inlet port will be gauged by measuring the flow ofair, at its predetermined pressure, into the hollow screw 26 and intothe original open end of the blank and passage P and thence out of boththe discharge orifice and the, first partially and then completelyformed, inlet port orifice in parallel. Knowing the rate of flow of airthat the discharge orifice passed at the predetermined pressure, theadditional flow will gauge, or permit one to gauge the desired,effective size of the inlet port while it is being formed. I prefer tocut and gauge the discharge orifice in this way before gauging the inletport in parallel with the discharge orifice as a matter of mechanicalconvenience; it being more awkward to hold the tip with the finishedinlet port freely vented to atmosphere than with the discharge orificeso vented. See FIG. 2. Prudence suggests that the relation between theeffective sizes of the inlet and discharge orifices as gaugedpneumatically in parallel, be checked as to each orifice when gaugedalone in each different size and style of nozzle tip. The sum of the airflow rates measured across each orifice separately in the differentspecific forms of my invention need not necessarily equal the flow ratethrough both in parallel.

As shown in FIG. 1 the nozzle N, comprises the nozzle tip 1, adapter 31as with female threads at its leftward, as viewed end to engage a spraygun or comprise a gun extension, all not shown.

When the adapter 31 functions as a gun extension it may be many timesthe length shown in the drawing and my enclose a valve stem, ofproportionate length and a valve closure element, not shown, adapted toseat on the entrance to the bore 33 and be moved to and from open andclosed position by the trigger of the gun. The nozzle also comprises atip-carrier portion 30, at its rightward end in the inclined socket 32ofwhich the tip is bonded or brazed in fixed, fluid-tight engagement.The bottom of the socket closes the turbulence chamber T, in therearward end of the passage P-T,. The hollow body of the adapter isnecked down to the axially aligned, short, small bore or channel 33which intersects the socket 32 and leads fluid to the inlet port I,,and/or provides a valve seat as mentioned above. See valve V, FIGS. 7and 10.

The nozzle N, is especially adapted to be made in small sizes for use inspraying the interior of small tubes and vessels such as the tube 34 ofFIG. 1. For instance, the tube may be from about /1 inch to 1 inchinside diameter and the nozzle only about one-fourth inch outsidediameter. The inclined upper face 35 of the carrier 30 permits the tipto protrude comfortably beyond the socket 32 without extending beyondthe one-quarter-inch projected cylindrical envelope of the adapter. Inthis arrangement the edges 36 of the spray fan pattern, shown in dottedlines, clear the carrier freely, and the liquid film at the root of theatomized fan is atomized so quickly that the film extends no more thanabout three thirtyseconds inch as indicated by the dotted line 37. Thispermits the spray fan to be well distributed and fully atomized beforereaching the interior surface of the tube 34 for the beneficent paintingor coating thereof.

To coat the interior of such a tube it is rotated rapidly, and thenozzle inserted into, and then withdrawn from, the tube at noticeablespeed. Spraying is preferably being confined to the entrance stroke.Presently incomplete experimental tests for applying lacquer internallyto 1 inch inside diameter tooth paste type tubes about 7 inches long,necked down, closed and screw capped at the far end, show that my nozzlein the form shown in FIG. I is probably the first nozzle, air-spray orairless, to effect entirely satisfactory and successful internal coatingof such tubes. On these tests, lacquer of 23.5 sec. viscosity by Ford 4millimeter cup at ambient temperature was sprayed at 140F. at 600 psi.The tubes were preheated to 270F. for 1 minute before spraying and bakedfor 4 minutes at 570F. after spraying. My nozzle provided goodatomization at the above mentioned low temperature and pressure withoutexcessive reduction of the lacquer. Excellent coverage of the wholeinterior of the tube including the sloping area and neck was obtainedwith the tip inclined at 60 as shown in FIG. 1; the nozzle beinginserted or Ianced" the full length of the tube twice. Exact prescribedfilm thickness (-15 microns) even in the difficult places was obtainedand maintained on a plurality of successively coated tubes;objectionable heavy build-up at any place being avoided, and noobjectionable bubbling occurring upon baking. A noticeable economy ofmaterial was obtained. Over-spray was reduced, if not wholly eliminated,and no plugging of the nozzle plagued the test operations.

While the nozzle tip is shown to be inclined about 60 to the axis of thenozzle, and tube, my invention in this form contemplates that the axisof the tip and socket may be angled from about 90 to the axis of thenozzle down to an acute angle.

, Throughout such a range, the inlet port will be inclinedcorrespondingly, from right angles like 1 in FIGS. 4, 7 and 10, to thelimit of practicable inclination as the tip is inclined more acutelythan shown in FIG. 1. Throughout the range of more acute inclinations ofthe tip to the axis of the adapter, my present understanding is that theinlet port should relate to and coact with the passage 33 to introduceliquid to the passage P at substantially right angles to the axis ofthepassage P. At the angle illustrated in FIG. 1, a fine cleaning probe maybe inserted through the passage 33, port I and out through the nozzleorifice O. The angle of the fan pattern between the dotted lines 36 mayalso be varied by the known techniques of selecting the shape and depthof the gash through the dome of the tip.

In FIG. 1 the nozzle tip is secured by metallic bonding or adhesiveattachment between the shank ofthe tip and the socket of the carrier.Compare the prior conventional attachment between the enlarged annularflange on the tip and the counterbore in the carrier as in FIGS. 4 and 7for example. Attachment ofthe tip in the socket gives a double benefit:a large bonding area, and a closure for the turbulence chamber.

In FIG. 4, the nozzle N comprises the conventional socalled adapter 40which integrally embraces the tip-carrier portion 41 in which the flangeof the portion 2, of the twopiece tip 2-2' is brazed and secured in thecounterbore 42. The portion 2 of the tip is carried and secured in thecentral bore 43 of the externally threaded, longitudinally perforate, asat 44, screw element 45, having threaded engagement with the adapter asat 46. The screw is forcibly movable axially with the axis of the bore43 aligned with the axis of the carrier whereby to align the axes of thetwo parts of the tip and corresponding parts of the passage P. Forwardmovement of the screw carries the rearward part 2 of the tip intofluid-tight contact with the forward part 2, completes the passage P andmakes the port I, the sole inlet of fluid into the turbulence chamber Tand approach passage P. The nozzle N is detachably secured to theforward end of a liquid or paint gun by a hollow nut 47, see also FIGS.7 and 10. Liquid or paint to be sprayed flows slowly from the gunthrough the perforations 44 in the screw to the inlet port I; where itis accelerated to, or about to, the discharge velocity from the orificeO. In this form of my invention cleaning of the nozzle tip is greatlyfacilitated. Removal of the screw and portion 2' of the tip from theadapter exposes the port 1 turbulence chamber T both halves of thepassage P and the orifice 0 all to cleaning by probes and solvent withentire facility. As will more fully appear below, new facility forcleaning the nozzle tips is also provided in the nozzles shown in FIGS.7-11.

The nozzle N of FIG. 7 comprises the tip 3, secured in the counterbore52 in the carrier 51 having a flange portion 50 and a resilientrubber-like ring 55 compressed between the flange 50 and the forwardface of the end of the gun G which seals the chamber between the gun andthe tip from leakage to atmosphere. A nut 57 threaded on the end of thegun and bearing on the flange forces the carrier and tip rearwardlycompressing the ring and sealing the chamber, and constraining the openrearward end of the tip into fluid-tight sealing contact with theforward planar face of the closure or turbulence plate 17 bonded toand/or carried in the central yielding perforate web 53 of the ring 55.Holes 54 in the web conduct fluid under pressure from the valve V of thegun to the inlet port I: ofthe nozzle tip; fluid pressure in the chamberbetween the valve and the port tending to augment the seals againstleakage between the plate and the tip as well as between the gun and thecarrier.

The carrier and tip are readily removed and exposed for cleaning. Thepassage P is wide open at the big, rear end, and the nozzle orifice O isfreely exposed internally and externally for washing, probing and airblasting. Novel also is the flush disposition of the inner face of theflange 50 in relation to the port 1 to permit a probe to be freelyinserted in the port without interference from the flange. When thecarrier and top are removed there is substantially no portion ofthecarrier radially opposite port I to obstruct the probe.

The modified form of nozzle N suggested in FIGS. 8 and 9, to whichreference has been made above, may incorporate the tip 4 with all theother elements of FIG. 7 and have substantially the same mode ofoperation and advantages, regard being had for the smaller turbulencechamber T, The nozzle tip 4 and closure turbulence plate 17 may also besubstituted in the combination shown in FIG. 4 for the two-piece tip2-2', the tip 4 replacing the tip portion 2, and the plate 17 beingcarried on the forward face of the screw 45 whereby to close the openupstream end of the tip 4. In this substitution the need to align thehalves of the passage P will be eliminated and the cleaning of the tip 4will present no greater problem than the tip 2 and carry its own inletport besides.

The modified form of my nozzle N shown in FIGS. 10 and 11 correspondsconsiderably to the form of FIG. 7, particularly to the gun, couplingnut and carrier which bear the same reference characters; the nozzle tip5 being the same as the tip 3 of the FIG. 7 except that it may be longerto accommodate the different form of closure 60 for the rearward endthereof. In the nozzle N the sealing and spacing ring has no central weband preferably, may otherwise correspond to the ring 55 for itsresilient, rubber-like qualities to seal the chamber between the gun andthe carrier, and space the rearward part ofthe tip and the closure fromthe forward end ofthe gun.

The ring 65 and the ring 55, as well as the closure 60 may be made of anelastomer or other materials chosen for their particular purposes andwith regard to the kind of fluids to which they are to be exposed.Rubber, Neoprene, Polypropolene, Nylon and Delrin exemplify suchmaterials. The closure 60 is preferred to have a snug stretched,resilient fit and have strength in shear to resist being extruded intothe turbulence chamber T The ring 55, FIG. 7, yields resiliently incompression and has internal shear strength, as found in O-rings andpiston cups, to resist deleterious extrusion into the gaps from whichthe fluid under pressure must be excluded and also brings the plate 17into simultaneous sealing contact with the rearward end of the tip. Thering 65 on the other hand has no double sealing chore and can be asunyielding as brass or steel given appropriate sealing surfaces, toengage the flange of the carrier and the end of the gun.

Cleaning the tip 5 while it is secured in its carrier 50 is as easy ascleaning the tip 3, FIG. 7, after the closure 60 has been removed fromthe end ofthe tip.

While I have illustrated and described certain preferred and modifiedforms and embodiments of my invention and the best modes presentlycontemplated by me for carrying out my invention, changes, equivalents,and improvements will occur to those skilled in the art who come tounderstand and enjoy my invention without departing from the essentialprinciples and precepts thereof. Therefore I do not want my patent to belimited to the forms, embodiments and modes herein specificallyillustrated and described, nor in any manner inconsistent with theprogress by which my invention has promoted the art.

I claim:

1. A spray nozzle tip having an internal passage closed at one end andhaving a spray orifice leading from the passage at its other end andhaving a side wall of appreciable thickness, a single side inlet to saidpassage spaced from said other end cut transversely through said sidewall, said inlet having an effec' tive area of opening into said passageequal to the effective area of said spray orifice plus or minus about25% and having substantially planar transverse faces tending to directfluid into said passage at right angles thereto.

2. A spray nozzle tip comprising an approach passage leading to a sprayorifice in one end and having an axis, a coaxial turbulence chamber atthe other end, and a single side inlet port for the nozzle tip adjacentsaid chamber, said inlet port having planar faces disposed transverselyof said axis and having an effective area of opening into said passageequal to the effective area of said spray orifice, plus or minus about25 percent.

3. The spray nozzle of claim 2 wherein said faces lie in planes whichmeet in a line that lies in a plane substantially normal to said axis.

4. In combination, a spray nozzle tip and a nozzle body, said nozzle tiphaving an approach passage at one end, a turbulence chamber at the otherend, and a single side inlet port between said chamber and said passage,said nozzle body having an axis and an internal passage, and having asocket at the downstream end of said body, said socket being inclinedwith respect to the axis and embracing said nozzle tip with said inletport communicating with said internal passage.

5. A spray nozzle tip having an axis, an outlet orifice aligned on saidaxis at one end, a coaxial turbulence chamber at the other end, and asingle side inlet port spaced from said orifice and having an effectivearea equal to the effective area of said outlet orifice plus or minusabout 25 percent and having one face disposed transversely of said axisadjacent said turbulence chamber.

6. A spray nozzle tip having an axis, an outlet orifice aligned on saidaxis at one end, a coaxial turbulence chamber at the other end, a singleside inlet port spaced from said orifice and having one face disposedtransversely of said axis adjacent said turbulence chamber, and acoaxial approach passage between said port and said orifice, saidpassage having asubstantially spherical dome through which said orificeis cut, said port being spaced from said dome about four to seven timesthe diameter ofthe said dome.

7. The nozzle tip of claim 6 in combination with a nozzle body having aninternal passage, an axis, a forwardly disposed socket inclined withrespect to said body axis and embracing said tip with said portcommunicating with the internal passage in said body and with saidoutlet orifice opening beyond the socket.

8. An airless spray nozzle tip having an annular wall of appreciablethickness, an internal longitudinal passage within said wall leading toan outlet orifice, said tip having a longitudinal axis and a lateralinlet port for said passage spaced from said outlet orifice andcomprising an inlet orifice cut through said wall; said port comprisinga slot having flat transverse faces which lie in planes that intersectin a line which lies in a plane substantially normal to said axis andhaving the bottoms of said slot in opposite parts of said wall, saidport directing fluid into said passage transversely of said axis andhaving an effective area equal to the effective area of said outletorifice plus or minus about 25 percent; the part of said passage betweensaid port and said outlet orifice comprising an approach passage for theoutlet orifice and the rest of the passage comprising a turbulencechamber.

9. The nozzle tip of claim 8 wherein the bottoms of the slot in theopposite parts of said wall are substantially flat and are symmetricallydisposed relative to said line, and intersect the internal surface ofsaid wall sharply at an acute angle.

10. The nozzle tip of claim 8 wherein the inlet port has no smallerminimum dimension than said discharge orifice, wherebysaid inlet porthas no more tendency to clog and become obstructed than said dischargeorifice.

11. An airless spray nozzle tip having a gallonage flow of water at 500p.s.i. as little as about 2 or 3 gallons per hour and having an annularwall of appreciable thickness, an internal longitudinal passage withinsaid wall terminating in one end in a dome having an outlet orificeslashed therein, said tip having a longitudinal axis and a lateral inletport for said passage spaced from said outlet orifice no more than aboutfour to seven times the diameter of said dome, said lateral inlet portcomprising an inlet orifice cut through said wall in the form of a slothaving flat transverse faces which lie in planes that intersect in aline which lies in a plane substantially normal to said axis and havingthe bottoms of said slot in opposite parts of said wall, said portdirecting fluid into said passage transversely of said axis, the part ofsaid passage between said port and said outlet orifice comprising anapproach passage for the outlet orifice and the rest of the passagecomprising a turbulence chamber.

12. An airless spray nozzle tip having an annular wall of appreciablethickness, an internal longitudinal passage within said wall leading toan outlet orifice, said tip having a longitudinal axis and a lateralinlet port for said passage spaced from said outlet orifice andcomprising an inlet orifice cut through said wall, said port comprisinga slot having flat transverse faces which lie in planes that intersectin a line which lies in a plane substantially normal to said axis andhaving the bottoms of said slot in opposite parts of said wall, saidport directing fluid into said passage transversely of said axis andinfluencing the stream of fluid entering said passage to be transverselyconstricted and made smaller than the width of said passage at the portand providing longitudinal avenues for turbulent fluid to flow from theturbulence chamber into the approach passage.

13. The nozzle tip of claim 12 in which said turbulence chamber hasabout the same volume as said approach passage.

14. In combination, a spray nozzle tip and a nozzle body, said nozzletip having an internal passage closed at one end and having a sprayorifice leading from the passage at its other end and having a singleside inlet to said passage spaced from said orifice, said nozzle bodyhaving a socket embracing said nozzle tip exteriorly of said one end andclosing said end, said nozzle body also having a passage leading to saidside inlet.

15. In combination, a spray nozzle tip and a nozzle tip carrier, saidtip having an internal passage closed at one end and having a sprayorifice leading from the passage at its other end and having a singleside inlet to said passage spaced from both said ends, said tip beingattached to said carrier adjacent said spray orifice, said carrier beingspaced away from said inlet and having substantially no portion disposedradially opposite said inlet.

16. An airless spray nozzle assembly adapted to be removably secured tothe forward end ofa spray gun, comprising a nozzle tip having a sprayorifice at its forward end and having an internal passage open at itsrearward end and leading to said spray orifice and having a lateralinlet port in the middle of the side thereof, and a nozzle tip carrierin which a forwardly disposed portion of said tip is secured and saidcarrier having its rearmost portion substantially flush with said inletorifice.

17. The spray nozzle assembly of claim 16 wherein the said end of saidgun and said carrier are adapted to be aligned and spaced apart tocomprise the rearward and forward ends of a chamber for fluid underpressure passing from the gun to the inlet port of said nozzle tip, withmeans for spacing said carrier from the said end of said gun andenclosing said chamber.

18. The nozzle assembly of claim 17 with attaching means for securingsaid carrier and said spacing means to said gun in fluid tightengagement therewith.

19. The nozzle assembly of claim 18 wherein the said rearward end ofsaid nozzle tip is disposed in said chamber with means for detachablyclosing said passage at the rearward open end thereof carried by saidspacing means.

20. The nozzle assembly of claim 19 in which said spacing means has aperforate resilient web adjacent the rearward end of said tip comprisingsaid closing means.

21. The nozzle assembly of claim 16 with a closure for the rearward endofthe tip detachably carried thereby.

22. The nozzle assembly of claim 21 with a sealing ring adapted to bedisposed between said carrier and said gun and forming a chamberenclosing the rearward end of said tip and said closure and conductingfluid from said gun to said inlet port.

23. An airless spray nozzle adapted to be removably secured to the endof a spray gun, comprising a nozzle tip having a forwardly disposed partwith an internal passage and a spray orifice leading herefrom at itsforward end and having a rearwardly disposed part with an internalpassage and a side inlet port therefor, a nozzle tip carrier in whichsaid forwardly disposed part is secured, and means supporting saidrearwardly disposed part for joining and separating said parts.

24. The nozzle tip of claim 1 including two pieces having a commonlongitudinal passage, a discharge orifice in one piece and a side inletport in the other piece.

25. A spray nozzle tip having an annular wall of appreciable thickness,an internal passage within said wall closed at one end and having aspray orifice at its other end, a single side inlet to said passage cutthrough said wall transversely of said passage between said ends andhaving an effective area equal to the effective area of said sprayorifice plus or minus about 25 percent, said inlet having substantiallyflat bottoms in transversely opposite parts of said wall that intersectthe internal surface of said wall at acute angles and tend to constructthe entering stream transversely.

26. An airless spray nozzle assembly adapted to be removably secured tothe forward end of a spray gun comprising a nozzle tip having a sprayorifice at its forward end and having an internal passage open at itsrearward end and leading to said spray orifice and having a lateralinlet port between said open end and said spray orifice, a nozzle tipcarrier in which a forwardly disposed portion of said tip is secured,means for spacing said carrier and nozzle tip from said end of said gunand defining a chamber for fluid under pressure between said gun andsaid inlet port, the rearward end of said nozzle tip being disposed insaid chamber and spaced from said gun, and a removable closure forclosing the rearward end of said passage and disposed to be pressedagainst said end by the static pressure of fluid in said chamber.

27. The nozzle assembly of claim 26 wherein said closure 15 yieldablysupported in said chamber by said spacing means, and is yieldablyengaged by the rearward end of said nozzle tip.

28. An airless spray nozzle tip having a flow rate of water less than 20gallons per hour at 500 p.s.i. and having an internal passage closed atone end and a spray orifice leading from the passage at its other endand having a side wall of appreciable thickness, a single side inlet tosaid passage spaced from said other end cut transversely through saidside wall, said inlet having substantially planar transverse facestending to direct fluid into said passage transversely thereof.

29. The nozzle tip of claim 28 having a flow rate of 2 to 3 gallonsofwater per hour at 500 p.s.i.

30. The combination of claim 4 of a size to coat the interior surfacesof containers ofless than 1 inch diameter.

31. The combination of claim 30 having a maximum diameter aboutone-fourth inch.

1. A spray nozzle tip having an internal passage closed at one end andhaving a spray orifice leading from the passage at its other end andhaving a side wall of appreciable thickness, a single side inlet to saidpassage spaced from said other end cut transversely through said sidewall, said inlet having an effective area of opening into said passageequal to the effective area of said spray orifice plus or minus about25% and having substantially planar transverse faces tending to directfluid into said passage at right angles thereto.
 2. A spray nozzle tipcomprising an approach passage leading to a spray orifice in one end andhaving an axis, a coaxial turbulence chamber at the other end, and asingle side inlet port for the nozzle tip adjacent said chamber, saidinlet port having planar faces dispoSed transversely of said axis andhaving an effective area of opening into said passage equal to theeffective area of said spray orifice, plus or minus about 25 percent. 3.The spray nozzle of claim 2 wherein said faces lie in planes which meetin a line that lies in a plane substantially normal to said axis.
 4. Incombination, a spray nozzle tip and a nozzle body, said nozzle tiphaving an approach passage at one end, a turbulence chamber at the otherend, and a single side inlet port between said chamber and said passage,said nozzle body having an axis and an internal passage, and having asocket at the downstream end of said body, said socket being inclinedwith respect to the axis and embracing said nozzle tip with said inletport communicating with said internal passage.
 5. A spray nozzle tiphaving an axis, an outlet orifice aligned on said axis at one end, acoaxial turbulence chamber at the other end, and a single side inletport spaced from said orifice and having an effective area equal to theeffective area of said outlet orifice plus or minus about 25 percent andhaving one face disposed transversely of said axis adjacent saidturbulence chamber.
 6. A spray nozzle tip having an axis, an outletorifice aligned on said axis at one end, a coaxial turbulence chamber atthe other end, a single side inlet port spaced from said orifice andhaving one face disposed transversely of said axis adjacent saidturbulence chamber, and a coaxial approach passage between said port andsaid orifice, said passage having a substantially spherical dome throughwhich said orifice is cut, said port being spaced from said dome aboutfour to seven times the diameter of the said dome.
 7. The nozzle tip ofclaim 6 in combination with a nozzle body having an internal passage, anaxis, a forwardly disposed socket inclined with respect to said bodyaxis and embracing said tip with said port communicating with theinternal passage in said body and with said outlet orifice openingbeyond the socket.
 8. An airless spray nozzle tip having an annular wallof appreciable thickness, an internal longitudinal passage within saidwall leading to an outlet orifice, said tip having a longitudinal axisand a lateral inlet port for said passage spaced from said outletorifice and comprising an inlet orifice cut through said wall; said portcomprising a slot having flat transverse faces which lie in planes thatintersect in a line which lies in a plane substantially normal to saidaxis and having the bottoms of said slot in opposite parts of said wall,said port directing fluid into said passage transversely of said axisand having an effective area equal to the effective area of said outletorifice plus or minus about 25 percent; the part of said passage betweensaid port and said outlet orifice comprising an approach passage for theoutlet orifice and the rest of the passage comprising a turbulencechamber.
 9. The nozzle tip of claim 8 wherein the bottoms of the slot inthe opposite parts of said wall are substantially flat and aresymmetrically disposed relative to said line, and intersect the internalsurface of said wall sharply at an acute angle.
 10. The nozzle tip ofclaim 8 wherein the inlet port has no smaller minimum dimension thansaid discharge orifice, whereby said inlet port has no more tendency toclog and become obstructed than said discharge orifice.
 11. An airlessspray nozzle tip having a gallonage flow of water at 500 p.s.i. aslittle as about 2 or 3 gallons per hour and having an annular wall ofappreciable thickness, an internal longitudinal passage within said wallterminating in one end in a dome having an outlet orifice slashedtherein, said tip having a longitudinal axis and a lateral inlet portfor said passage spaced from said outlet orifice no more than about fourto seven times the diameter of said dome, said lateral inlet portcomprising an inlet orifice cut through said wall in the form of a slothaving fLat transverse faces which lie in planes that intersect in aline which lies in a plane substantially normal to said axis and havingthe bottoms of said slot in opposite parts of said wall, said portdirecting fluid into said passage transversely of said axis, the part ofsaid passage between said port and said outlet orifice comprising anapproach passage for the outlet orifice and the rest of the passagecomprising a turbulence chamber.
 12. An airless spray nozzle tip havingan annular wall of appreciable thickness, an internal longitudinalpassage within said wall leading to an outlet orifice, said tip having alongitudinal axis and a lateral inlet port for said passage spaced fromsaid outlet orifice and comprising an inlet orifice cut through saidwall, said port comprising a slot having flat transverse faces which liein planes that intersect in a line which lies in a plane substantiallynormal to said axis and having the bottoms of said slot in oppositeparts of said wall, said port directing fluid into said passagetransversely of said axis and influencing the stream of fluid enteringsaid passage to be transversely constricted and made smaller than thewidth of said passage at the port and providing longitudinal avenues forturbulent fluid to flow from the turbulence chamber into the approachpassage.
 13. The nozzle tip of claim 12 in which said turbulence chamberhas about the same volume as said approach passage.
 14. In combination,a spray nozzle tip and a nozzle body, said nozzle tip having an internalpassage closed at one end and having a spray orifice leading from thepassage at its other end and having a single side inlet to said passagespaced from said orifice, said nozzle body having a socket embracingsaid nozzle tip exteriorly of said one end and closing said end, saidnozzle body also having a passage leading to said side inlet.
 15. Incombination, a spray nozzle tip and a nozzle tip carrier, said tiphaving an internal passage closed at one end and having a spray orificeleading from the passage at its other end and having a single side inletto said passage spaced from both said ends, said tip being attached tosaid carrier adjacent said spray orifice, said carrier being spaced awayfrom said inlet and having substantially no portion disposed radiallyopposite said inlet.
 16. An airless spray nozzle assembly adapted to beremovably secured to the forward end of a spray gun, comprising a nozzletip having a spray orifice at its forward end and having an internalpassage open at its rearward end and leading to said spray orifice andhaving a lateral inlet port in the middle of the side thereof, and anozzle tip carrier in which a forwardly disposed portion of said tip issecured and said carrier having its rearmost portion substantially flushwith said inlet orifice.
 17. The spray nozzle assembly of claim 16wherein the said end of said gun and said carrier are adapted to bealigned and spaced apart to comprise the rearward and forward ends of achamber for fluid under pressure passing from the gun to the inlet portof said nozzle tip, with means for spacing said carrier from the saidend of said gun and enclosing said chamber.
 18. The nozzle assembly ofclaim 17 with attaching means for securing said carrier and said spacingmeans to said gun in fluid tight engagement therewith.
 19. The nozzleassembly of claim 18 wherein the said rearward end of said nozzle tip isdisposed in said chamber with means for detachably closing said passageat the rearward open end thereof carried by said spacing means.
 20. Thenozzle assembly of claim 19 in which said spacing means has a perforateresilient web adjacent the rearward end of said tip comprising saidclosing means.
 21. The nozzle assembly of claim 16 with a closure forthe rearward end of the tip detachably carried thereby.
 22. The nozzleassembly of claim 21 with a sealing ring adapted to be disposed betweensaid carrier and said gun and forming a chamber enclosing the rearWardend of said tip and said closure and conducting fluid from said gun tosaid inlet port.
 23. An airless spray nozzle adapted to be removablysecured to the end of a spray gun, comprising a nozzle tip having aforwardly disposed part with an internal passage and a spray orificeleading herefrom at its forward end and having a rearwardly disposedpart with an internal passage and a side inlet port therefor, a nozzletip carrier in which said forwardly disposed part is secured, and meanssupporting said rearwardly disposed part for joining and separating saidparts.
 24. The nozzle tip of claim 1 including two pieces having acommon longitudinal passage, a discharge orifice in one piece and a sideinlet port in the other piece.
 25. A spray nozzle tip having an annularwall of appreciable thickness, an internal passage within said wallclosed at one end and having a spray orifice at its other end, a singleside inlet to said passage cut through said wall transversely of saidpassage between said ends and having an effective area equal to theeffective area of said spray orifice plus or minus about 25 percent,said inlet having substantially flat bottoms in transversely oppositeparts of said wall that intersect the internal surface of said wall atacute angles and tend to construct the entering stream transversely. 26.An airless spray nozzle assembly adapted to be removably secured to theforward end of a spray gun comprising a nozzle tip having a sprayorifice at its forward end and having an internal passage open at itsrearward end and leading to said spray orifice and having a lateralinlet port between said open end and said spray orifice, a nozzle tipcarrier in which a forwardly disposed portion of said tip is secured,means for spacing said carrier and nozzle tip from said end of said gunand defining a chamber for fluid under pressure between said gun andsaid inlet port, the rearward end of said nozzle tip being disposed insaid chamber and spaced from said gun, and a removable closure forclosing the rearward end of said passage and disposed to be pressedagainst said end by the static pressure of fluid in said chamber. 27.The nozzle assembly of claim 26 wherein said closure is yieldablysupported in said chamber by said spacing means, and is yieldablyengaged by the rearward end of said nozzle tip.
 28. An airless spraynozzle tip having a flow rate of water less than 20 gallons per hour at500 p.s.i. and having an internal passage closed at one end and a sprayorifice leading from the passage at its other end and having a side wallof appreciable thickness, a single side inlet to said passage spacedfrom said other end cut transversely through said side wall, said inlethaving substantially planar transverse faces tending to direct fluidinto said passage transversely thereof.
 29. The nozzle tip of claim 28having a flow rate of 2 to 3 gallons of water per hour at 500 p.s.i. 30.The combination of claim 4 of a size to coat the interior surfaces ofcontainers of less than 1 inch diameter.
 31. The combination of claim 30having a maximum diameter about one-fourth inch.